Spectrophotometric determination of basicity constants. Part III. Phenylureas
The basicity constants KBH+ of seven substituted phenylureas have been evaluated in sulphuric acid at 25°. The protonation equilibria follow the HA acidity function and –pKBH+ of 12 substituted phenylureas correlate well with Hammett σ. The site of protonation is discussed.